Regarding my first "??? sky/skies" (some hear darkened/blackened, but I don't) - I think it might refer to a location, but I can't discern which.

I am quite aware of the problem with the first line of the chorus! But I couldn't come up with anything better.

And the second ??? is quite impossible to hear, due to the high falsetto. Something about reforging the Narsil/Andúril seems to fit though. I might give the song a second listen when I get home from work.